In any vehicle, a fuel meter is a necessary instrument for indicating fuel quantity. A driver can thus estimate the distance which the remaining fuel can accommodate and what time additional fuel should be supplied.
There are several types of fuel indicators embodied in the prior art. Examples of such prior art include serial coils, parallel coils and electro-thermo couples types, and these known fuel indicators require a rheostat or an electro-thermo couple which is actuated by a floating element placed in a fuel tank, and the rheostat or the electro-thermo couple operates a pointer for inclination to indicate roughly at "F", "E", "1/4", "1/2" or "3/4" position printed on a fuel meter.
At least the following drawbacks are presented by the conventional fuel meters:
A. The pointer of the fuel meter indicates roughly "F", "E", "1/4", "1/2" or "3/4". Thus, the correct fuel quantity remaining in the fuel tank is not accurately indicated.
B. Since the pointer type fuel meter is not a precision indicator, a viewing error is caused by different angles and distances from the driver's eyes to the fuel meter.
C. After vehicle start-up, time is required for the pointer to settle into a normal position.
D. A driver cannot measure the correct fuel consumption or quantity of fuel remaining in the tank since a ratio of the fuel consumption and the declining angle of the pointer is not linear or constant.
E. The driver cannot set a predetermined fuel quantity which reaches a predetermined capacity of the fuel tank. Therefore, there is no way of knowing if fuel is overflowing from the fuel tank during filling thereof, such as when the fuel input is exceeding the maximum capacity of the fuel tank, and the filling gun is not an automatic shut-off type.
F. Prior art fuel indicating systems include rheostats or electro-thermo couples, and such elements are costly since some contact parts should include costly metal such as platinum or platinum alloy. Moreover, these components may malfunction due to heating, oxidation and bed contact.
G. It is difficult for a driver to find out the cause of an unreasonable consumption of fuel if this fuel consumption is caused by leakage. Thus, energy is wasted as the indicating mechanisms of prior art fuel meters are only brief and not precise.